Overhead Door Efficiency Project
At Armstrong International
Nathan Christensen, Research Assistant
Ryan Kamm, Research Assistant
Western Michigan University
College of Engineering and Applied Science
Objectives
• Analyze the cost associated with running the
overhead door heaters on an annual basis.
• Analyze the air movement through the
overhead doors in Plant 1 and Plant 2/3.
• Provide alternative solutions to help increase
the efficiency of the overhead doors.
Basic Door Information
• Plant 1
– 12’ Wide X 13’8’’ Tall
– 40 second cycle time (Time needed to open and
immediately close.)
– 460,000 Btu Heater
• 80% Efficient
• Plant 2/3
– 12’ Wide X 12’ Tall
– 30 second cycle time (Time needed to open and
immediately close.)
– 402,000 Btu Heater
• 80% Efficient
Overhead Door Heater Cost
• Estimated cost per heating season with an average cycle
time of 3.5 minutes, with 88 cycles per day for 120 days:
– $4,048
• Estimated cost per heating season with an average cycle
time of 1 minute, with 88 cycles per day for 120 days:
– $1,110
• Possible door heater savings by door cycle time reduction:
– $2,938
• Average open time of 1 minute represents a
baseline best case scenario. The actual active
heater and boiler time could be several minutes in
length.
Boiler Estimated Cost
• Boiler cost for the 2009 heating season:
– $66,893
• Very close to an average door cycle time of 3.5 minutes for
the 120 day heating season.
• Boiler cost based on a 1 minute average cycle
time:
– $18,520
• Current value based on costs needed to run the boiler for
a120 day heating season.
• Savings possible through door cycle time
reduction from 3.5 minutes to 1 minute:
– $48,373
Heat Energy Lost
• Indoor temperature during heating season
was assumed to be 75 degrees.
• The cutoff outdoor temperature for the
heaters to run was assumed to be 55 degrees.
• Energy loss was calculated for an insideoutside temperature difference range of 20
degrees minimum to 75 degrees maximum
with 45 degrees being the average.
Heat Energy Lost Continued
Heat Loss Through Door
Area of Door 1 (A):
Area of Door 2 (A):
Specific Heat of Air (Cp):
Avg. Velocity (v):
Δ Temp (min):
Δ Temp(avg):
Δ Temp (max):
Density of Air (ρ):
Q = v * A * Δ Temp * Cp*ρ
Q loss door 1(min):
Q loss door 1(max):
Q loss door 1 (avg):
Q loss door 2(min):
Q loss door 2(max):
Q loss door 2 (avg):
144
162
0.0288
5.87
20
45
75
0.075
ft^2
ft^2
BTU/lb-°F
ft/s
°F
°F
°F
lb/ft³
167974
460102
295780
BTUhr
BTU/hr
BTU/hr
147890
517615
332752
BTU/hr
BTU/hr
BTU/hr
Cost Based on Energy Required
to Heat Incoming Air
• Costs were calculated based on a 3.5 minute
cycle time.
• Door 1 loses an average of 295,780 BTU/hr for
a cost per heating season of $1,111.43
• Door 2 loses an average of 332,753 BTU/hr for
a cost per heating season of $1250.34.
Overhead Door Efficiency
Solutions
• Driver Education
– Signs to serve as reminders for the drivers.
• Overhead Door Modification
– Changing how the doors work and the size of their
opening.
• Magnetic Proximity Sensor System
– Detects forklifts as they enter and exit a given zone,
opening and closing the doors as necessary.
• Temperature Control Valve
– Will limit the amount of energy used by the heaters
based on the temperature outside.
Driver Education and
Door Modification
• During our study, the drivers demonstrated the ability to keep door
cycle times to 1 minute or less.
– Education
– Signs
– Incentives
• Changing the height and speed at which the doors open can also
bring simple and meaningful results.
– Limiting the open height to 10’ would save 15 seconds between the
two doors.
– The total cost per heating season for a 3.5 minute cycles is $4,048.
– Estimated savings of $289 annually for a 15 second reduction.
– Changing out the gears would also help the doors open faster,
lessening the time the heaters ran.
Proximity Sensor
• Door Loop Setup System:
• Construction Equipment:
• Labor & Other Materials:
$714.00
$100.00
$300.00
• Total Estimated Cost:
$1,114.00
– Costs include hardware needed for the system as
well as construction equipment and labor.
• Return on Investment: Approximately 4 Months.
Temperature Control Valve
• Hardware:
– Valve:
$1,500
– Controller (Sensor): $1,000
– Installation:
$500
– Total Cost:
~$3,000
• Estimated 37% reduction in energy use per
heating season yielding $24,750 in savings per
year.
• Return on Investment estimated to be
approximately 2 months.
Summary Of All Options
Cost To Implement
Given Solution (All
costs are estimates.)
Savings
Return on Investment
(ROI figures are all
estimates.)
Driver Education/Door
Modification
$1,000
$578 (Based on an
average open door
time reduction of 30
seconds.)
2 years (maximum)
Proximity Sensor
$1,114
$2,938
4 months
Temperature Control
Valve
$3,000
$24,750
2 months
Proximity Sensor and
Temperature Control
Valve
$4,114
$28,493
2 months
Driver Education/
Door Modification and
Temperature Control
Valve
$4,000
$25,328 (minimum)
2 months
Overhead Door
Solution
Conclusions
• The overhead door heaters are consuming
considerably less heat than the boilers are generating.
This excess heat loss makes up for the bulk of the cost.
• During our time spent recording door cycles, we
concluded that drivers can keep the doors open for less
than 1 minute.
• Several low cost solutions are available that can
decrease how long the doors are open. These
solutions are generally able to repay themselves in less
than 2 years and would begin to generate money for
the company afterwards.
Thank You!
• Armstrong International
– Greg Martin
– Ed Kirchner
– Jim Arjmand
• Western Michigan University
– Dr. John Patten
– Dr. David Meade
– All other colleagues